App Crashes when receiving FCM Notification on Foreground works on Background

Question

I've added Firebase Cloud Messaging on my app by following directions on the Documentation. It seems to work fine but app crashes when receiving on Foreground but works perfectly when it is receiving close.

MANIFEST

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com. gumangan. uecficenterslist">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <service
        android:name=".MyFirebaseMessagingService"
        android:enabled="true"
        android:exported="false">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
        </intent-filter>
    </service>
    <!-- Set custom default icon. This is used when no icon is set for incoming notification messages.
    <meta-data
        android:name="com.google.firebase.messaging.default_notification_icon"
        android:resource="@drawable/ic_menu_camera" />
    <!-- Set color used with incoming notification messages. This is used when no color is set for the incoming
         notification message.
    <meta-data
        android:name="com.google.firebase.messaging.default_notification_color"
        android:resource="@color/colorAccent" />

    <activity
        android:name="com.google.android.gms.ads.AdActivity"
        android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
        tools:replace="android:theme" />
    <activity
        android:name=".MenuActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".CentersActivity"
        android:label="@string/title_activity_hymns"
        android:launchMode="singleTop"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>

        <meta-data
            android:name="android.app.searchable"
            android:resource="@xml/searchable" />
    </activity>
    <activity
        android:name=".CentersDetailActivity"
        android:parentActivityName=".CentersActivity">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.gumangan.uecficenterslist.CentersActivity" />
    </activity>
    <activity
        android:name=".YouTubeActivity"
        android:label="@string/title_activity_web"
        android:theme="@style/AppTheme.NoActionBar"></activity>
    <activity
        android:name=".AboutActivity"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".AffiliateActivity"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".TermsActivity"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".WarningActivity"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".ShareActivity"
        android:label="@string/title_activity_share"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".SupportActivity"
        android:label="@string/title_activity_support"
        android:theme="@style/AppTheme.NoActionBar" />
    <activity
        android:name=".SubmitActivity"
        android:label="@string/title_activity_submit"
        android:theme="@style/AppTheme.NoActionBar">
    </activity>

</application>
</manifest>

DEPENDENCIES

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

apply plugin: 'io.fabric'
android {
/* TODO: Don't forget to change versionCode and versionName when updating for final building */
compileSdkVersion 28
defaultConfig {
    applicationId "com. gumangan. uecficenterslist"
    minSdkVersion 16
    targetSdkVersion 28
    versionCode 8
    versionName "1.7"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

    vectorDrawables.useSupportLibrary = true
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

}

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"

implementation 'com.android.support.constraint:constraint-layout:1.1.3'
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:support-v4:28.0.0'
implementation 'com.android.support:design:28.0.0'
implementation 'com.android.support:cardview-v7:28.0.0'
implementation 'com.android.support:customtabs:28.0.0'
implementation 'com.android.support:support-core-utils:28.0.0'

implementation 'com.intuit.sdp:sdp-android:1.0.5'
implementation 'com.intuit.ssp:ssp-android:1.0.5'

implementation 'com.google.android.gms:play-services-ads:17.2.1'
implementation 'com.google.firebase:firebase-core:16.0.9'
implementation 'com.google.firebase:firebase-ads:17.2.1'
implementation 'com.crashlytics.sdk.android:crashlytics:2.10.1'

implementation 'com.google.firebase:firebase-messaging:18.0.0'

testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}
apply plugin: 'com.google.gms.google-services'

MyFirebaseMessagingService.kt

package com.gumangan.uecficenterslist

import android.util.Log
import com.google.firebase.messaging.FirebaseMessagingService
import com.google.firebase.messaging.RemoteMessage
import com.gumangan.uecficenterslist.CentersActivity.Companion.TAG

class MyFirebaseMessagingService : FirebaseMessagingService() {

override fun onMessageReceived(remoteMessage: RemoteMessage?) {
    // ...

    // TODO(developer): Handle FCM messages here.
    // Not getting messages here? See why this may be:
    Log.d(TAG, "From: ${remoteMessage?.from}")

    // Check if message contains a data payload.
    remoteMessage?.data?.isNotEmpty()?.let {
        Log.d(TAG, "Message data payload: " + remoteMessage.data)

        if (/* Check if data needs to be processed by long running job */ true) {
            // For long-running tasks (10 seconds or more) use WorkManager.
            scheduleJob()
        } else {
            // Handle message within 10 seconds
            handleNow()
        }
    }

    // Check if message contains a notification payload.
    remoteMessage?.notification?.let {
        Log.d(TAG, "Message Notification Body: ${it.body}")
    }

    // Also if you intend on generating your own notifications as a result of a received FCM
    // message, here is where that should be initiated. See sendNotification method below.
}

private fun handleNow(): Any {
    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}

private fun scheduleJob(): Any {
    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}

/**
 * Called if InstanceID token is updated. This may occur if the security of
 * the previous token had been compromised. Note that this is called when the InstanceID token
 * is initially generated so this is where you would retrieve the token.
 */
override fun onNewToken(token: String?) {
    Log.d(TAG, "Refreshed token: $token")

    // If you want to send messages to this application instance or
    // manage this apps subscriptions on the server side, send the
    // Instance ID token to your app server.
    sendRegistrationToServer(token)
}

private fun sendRegistrationToServer(token: String?) {
    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}


}

Well the app is receiving Notifications on when it is Kill and Background but it crashes when Receiving Notifications on Foreground.

V/FA: Connection attempt already in progress
E/AndroidRuntime: FATAL EXCEPTION: Firebase-MyFirebaseMessagingService
Process: com.gumangan.uecficenterslist, PID: 15201
kotlin.NotImplementedError: An operation is not implemented: not implemented
    at com.gumangan.uecficenterslist.MyFirebaseMessagingService.scheduleJob(MyFirebaseMessagingService.kt:44)
    at com.gumangan.uecficenterslist.MyFirebaseMessagingService.onMessageReceived(MyFirebaseMessagingService.kt:23)
    at com.google.firebase.messaging.FirebaseMessagingService.zzd(Unknown Source)
    at com.google.firebase.iid.zzb.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
    at com.google.android.gms.common.util.concurrent.zza.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:761)

Answer 1

As per the Mohit's answer remove TODO(...) and also remove return type :Any from function declaration.

For example replace below function,

private fun scheduleJob(): Any {
    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}

with,

private fun scheduleJob() {
    // TODO : "not implemented"
}

Answer 2

Just remove

TODO("not implemented")

TODO(...) is Kotlin function which always throws NotImplementedError. If you want to mark something with TODO but to not throw an exception - just use TODO with comments:

Hope this helps!!!